1. Field of Invention
The present invention relates generally to the field of telecom/datacom equipment. More specifically, the present invention is related to telecom/datacom equipment conforming to different mechanical standards, which utilizes common basic components of the equipment.
2. Background
A telecommunications or data communications vendor who sells equipment to service providers must provide equipment which meets a number of requirements. Some of these requirements are dictated by industry standards, while others are common xe2x80x9cknownxe2x80x9d criteria.
Particularly, vendors that sell equipment to service providers in a global market find themselves facing conflicting requirements from different service providers over the world. It is the goal of the vendor engineering team to support all requirements with minimum engineering efforts and with minimum changes in the basic parts of the products, such as the system and I/O modules. Changes cause multiple part numbers, increased support, increased risk for mistakes etc.
The mechanical design of the telecom/datacom equipment is one of the fields where service providers are mostly involved by standardization and special requirement. The equipment has to fit into the racks of the service providers, has to be accessed and serviced easily, has to conform to the cooling mechanism the service provider requires, in addition to meeting other requirements.
There are primarily two standards common in the world that have dominion over the mechanical design of telecom/datacom equipment. One standard is the ETSI (European Telecommunications Standards Institute) standard that is common in Europe, while the other is the NEBS (Network Equipment Building Systems) standard that is typically requested in the U.S.A.
The following provides a general overview of the basic and most common requirements requested by the ETSI standards and the European service providers:
Equipment should not exceed 300 mm deep (to fit in a 300 mm rack).
Access to equipment is only from the front. The 300 mm ETSI rack has no rear access.
Therefore, cables/connections cannot be connected to the rear of the equipment.
To improve the serviceability and reliability of the system, replacing a system module does not involve disconnecting or removing cables.
Airflow is from bottom to top. Whenever possible, convection cooling is preferred.
On the other hand, the following provides a general overview of the basic and most common requirements requested by the NEBS standards and American service providers:
All connections/cables should be connected on the rear side of the rack (and therefore on the rear side of the equipment).
System modules should be plugged and accessed from the front side of the rack.
Indicators should be viewed from the front.
To improve the serviceability and reliability of the system, replacing a system module does not involve disconnecting or removing cables.
Airflow should be from the front to the backside.
As illustrated by the above points, generally, the only common requirement of both standards is the improvement to serviceability (and reliability) by separating the input/output connections (cables) from the system modules. This means that when a system module fails, the technician will need only to replace the module and will not need to disconnect cables. However, there is a main difference between the requirements as to the side in which the system is xe2x80x9cservicedxe2x80x9d.
The ETSI standard requires that all cables and connectors and also the system cards will be plugged from the frontxe2x80x94so it is said that the xe2x80x9cservicexe2x80x9d to the equipment can be done only from the front.
For the NEBS requirement, the cable connections should be on the rear, while indicators and system modules are accessed from the front. This means that the xe2x80x9cservicexe2x80x9d to the equipment is from both sides of the rack.
For a fuller understanding behind the requirements, it is important to know how a service provider telecom hall is built. The equipment racks are arranged in rows, each row of racks has aisles on both sides. For NEBS racks, there is a xe2x80x9cfrontxe2x80x9d aisle and a xe2x80x9cbackxe2x80x9d aisle. On the front aisle are all the equipment indicators and system modules. On the back aisle all the cables are connected. In addition, the hall room air-condition is coming in to the front aisle and exhausted on the back aisle.
For ETSI racks, however, each row of racks is built of back to back racks, so actually both aisles xe2x80x9cseexe2x80x9d the front of the equipment with access both to cables, indicators and cards.
Generally, there is the need for alternative equipment that, while differing in, mechanical design due to the standard supported, are designed in such a way that the basic components of the equipment, e.g. system modules, interface modules, power supply modules, fan modules, etc., do not need to be designed differently for the two designs, i.e. the basic components are able to be designed to be useable in either.
ETSI/NEBS housing structures and backplanes are provided to support their respective standards with minimum engineering efforts for their design and minimum changes in the basic components of telecom/datacom equipment.
The ETSI compliant structure, generally, has a lower enclosure region for housing system modules of the telecom/datacom equipment and an upper enclosure region for housing interface modules of the telecom/datacom equipment. Slots are located on each of the front walls defining each enclosure region for receiving the system and interface modules of the system. When the ETSI compliant structure is assembled with the ETSI backplane, the backplane is disposed in the interior of the structure along a common back wall. A lower portion of the backplane, including connectors for receiving connectors of the system modules, is substantially contained in the lower enclosure region and an upper portion, including connectors for receiving connectors of the interface modules, extends into and is substantially contained within the upper enclosure region.
A fan enclosure region is located beneath the lower enclosure region for housing a fan module. A fan slot is located on the front wall of the structure for receiving the fan module and a portion of the backplane, including a fan connector for receiving connectors of the fan module, extends into and is substantially enclosed within fan enclosure region. Preferably, power supply slots are located adjacent to and coextensive with system module slots on the front wall of lower enclosure region for receiving power supply modules. The power supply modules are enclosed within the lower enclosure region and connectors of the power supply modules connect to connectors located on backplane adjacent to and coextensive with the system module connectors on the backplane.
The NEBS compliant structure, generally, has a front enclosure region for housing system modules of the telecom/datacom equipment and a rear enclosure region for housing interface modules of the telecom/datacom equipment. Slots are located on the front wall defining the front enclosure region for receiving the system modules of the system and on the rear wall defining the rear enclosure region for receiving interface modules of the system. When the NEBS compliant structure is assembled with the NEBS backplane, the backplane is disposed in the interior of the structure along a plane dividing the front enclosure region from the rear enclosure region. Since the backplane is located on the mid part of the structure, it is commonly known in the art as a xe2x80x9cmid-planexe2x80x9d. In similar structures the term xe2x80x9cmid-planexe2x80x9d is sometimes used instead of xe2x80x9cbackplane.xe2x80x9d However, throughout the rest of this disclosure, rather than mid-plane for the NEBS chassis, backplane will be used. A first surface of the backplane, including connectors for receiving connectors of the system modules, faces the front enclosure region and a second surface, opposite said first surface, including connectors for receiving connectors of the interface modules faces the rear enclosure region.
A fan enclosure region is located beneath the front enclosure region for housing a fan module and an air exhaust tunnel is located above the front and rear enclosure regions. A fan slot is located on the front wall of the structure for receiving the fan module and a portion of the backplane, including a fan connector on the first surface for receiving connectors of the fan module, extends into and is substantially enclosed within fan enclosure region. Preferably, power supply slots are located adjacent to and coextensive with system module slots on the front wall of front enclosure region for receiving power supply modules. The power supply modules are enclosed within the front enclosure region and connectors of the power supply modules connect to connectors located on backplane adjacent to and coextensive with the system module connectors on the backplane.